1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device.
2. Description of the Related Art
Demand has arisen for protecting, against physical alteration and analysis, a circuit mounted on a semiconductor integrated circuit device for holding data requiring high security such as personal information. In the semiconductor integrated circuit device described in Japanese Patent Laid-Open No. 2006-012159, a wiring line is formed on a circuit to be protected. When detecting a change in voltage of this wiring line, a detection circuit of the semiconductor integrated circuit device determines that the wiring line has been altered. However, a focused ion beam (FIB) apparatus has recently become usable. When using the FIB apparatus, it is possible to cut a wiring line by emitting an ion beam from the front surface of a semiconductor integrated circuit device, and deposit a wiring metal. Even when a circuit is protected using the technique described in Japanese Patent Laid-Open No. 2006-012159, therefore, if the FIB apparatus is used to deposit a wiring metal so as to bypass a portion to be analyzed and apply a predetermined voltage, it is possible to cause a recognition error, that is, it is possible to cause the determination operation of the detection circuit to detect a normal state instead of an abnormal state.